Re: [PATCH 10 of 16] stop useless vm trashing while we wait the TIF_MEMDIE task to exit

Christoph Lameter
2007-06-11T16:57:59Z

On Mon, 11 Jun 2007, Andrea Arcangeli wrote:

> On Mon, Jun 11, 2007 at 09:07:59AM -0700, Christoph Lameter wrote:
> > Filtering tasks is a very expensive operation on huge systems. We have had
>
> Come on, oom_kill.c only happens at oom time, after the huge complex
> processing has figured out it's time to call into oom_kill.c, how can
> you care about the performance of oom_kill.c? Apparently some folks
> prefer to panic when oom triggers go figure...

Its pretty bad if a large system sits for hours just because it cannot
finish its OOM processing. We have reports of that taking 4 hours!

> In turn killing the current task so that oom_kill.c is faster, is
> quite a dubious argument.

It avoids repeated scans over a super sized tasklist with heavy lock
contention. 4 loops for every OOM kill! If a number of processes will be
OOM killed then it will take hours to sort out the lock contention.

Want this as a a SUSE bug?